非虚拟成员的无效设置 - 在接口上？

Question

使用Moq进行单元测试时,出现以下错误:

Message: System.NotSupportedException : 
    Invalid setup on non-virtual (overridable in VB) member: 
    cm => cm.AppSettings[It.IsAny<string>()]

根据这些发现,我理解最好使用Moq的抽象类或接口.

• 为什么我想要模拟的属性需要是虚拟的？
• 当类在Service Project中时,Moq会在不可覆盖的成员上抛出无效设置
• 非虚拟(在VB中可覆盖)成员上的设置无效
• Moq:非可覆盖成员的设置无效:x => x.GetByTitle("asdf")

简而言之,我完成了我的作业.=)

但是,如果我实际使用的是接口呢？

ConfigurationServiceTests

[TestFixture]
public class ConfigurationServiceTests {
    [Test]
    public void DialectShouldQueryConfigurationManagerAppSettings() {
        // Given
        configurationManagerMock
            .Setup(cm => cm.AppSettings[It.IsAny<string>()])
            .Returns(It.IsAny<string>());

        // When
        var dialect = configurationService.Dialect;

        // Then
        dialect.Should().BeOfType<string>();
        configurationManagerMock.Verify(cm => cm.AppSettings[It.IsAny<string>()]);
    }

    [SetUp]
    public void ConfigurationServiceSetUp() {
        configurationManagerMock = new Mock<IConfigurationManager>();
        configurationService = 
            new ConfigurationService(configurationManagerMock.Object);
    }

    private Mock<IConfigurationManager> configurationManagerMock;
    private IConfigurationService configurationService;
}

IConfigurationManager

public interface IConfigurationManager {
    NameValueCollection AppSettings { get; }
    ConnectionStringSettingsCollection ConnectionStrings { get; }
}

IConfigurationService

public interface IConfigurationService {
    string ConnectionDriver { get; }
    string ConnectiongString { get; }
    string Dialect { get; }
}

ConfigurationService

public class ConfigurationService : IConfigurationService {
    public ConfigurationService(IConfigurationManager configurationManager) {
        this.configurationManager = configurationManager;
    }

    public string ConnectionDriver {
        get { return configurationManager.AppSettings["ConnectionDriver"]; }
    }

    public string ConnectionString {
        get { 
            return configurationManager
                .ConnectionStrings[ConnectionStringKey]
                .ConnectionString; 
        }
    }

    public string Dialect { 
        get { return configurationManager.AppSettings[DialectKey]; } 
    }

    private readonly IConfigurationManager configurationManager;

    private const string ConnectionStringKey = "DefaultConnectionString";
    private const string DialectKey = "Dialect";
}

为什么我创建了IConfigurationManager界面？

• 单元可测试配置管理器

除此之外,我想在我的生产代码中使用Ninject直接绑定它.所以我不需要具体的接口实现,因此我对上述异常感到非常惊讶.

kernel.Bind<IConfiguration>().To<ConfigurationManager>().InSingletonScope();

这样做可以让我对我进行单元测试ConfigurationService.

任何的想法？

Answer 1

你试图模拟索引器NameValueCollection而不是你的属性getter.

你需要做一些事情(注意SetupGet而不是Setup):

  .SetupGet(cm => cm.AppSettings).Returns(....)

如果你想要"mocked"集合返回"任何东西",你可能需要覆盖实际的类(检查是否有可能).

如果您知道要查找的设置 - 从Mock返回填充的集合可能是一个选项:

 configurationManagerMock  
   .SetupGet(cm => cm.AppSettings)
   .Returns(new NameValueCollection { {"SettingName", "Value"}});

另一个选择是返回一些自定义界面,或者IDictionary<string,string>你也可以模拟索引:

interface IConfigurationManager 
{
   IDictionary<string,string> AppSettings { get; }
   ...